Doctor blade and supporting structure



Feb. 1, 1966 a. KEITH DOCTOR BLADE AND SUPPORTING STRUCTURE 3 Sheets-Sheet 1 Filed Dec. 29, 1961 mvamqx Q'ar %nafffbz O EYE.

INVENTOR i/Z?! S Sheets-Sheet 2 lllllllllllllllnum 2 \km E LiufliQfl Feb. 1, 1966 ca. KEITH DOCTOR BLADE AND SUPPORTING STRUCTURE Feb. 1, 1966 G. KEITH DOCTOR BLADE AND SUPPORTING STRUCTURE 3 Sheets-Sheet 5 Filed D604 29, 1961 INVENTOR. 7

United States Patent 3,232,269 DUCTUR BLADE AN!) SUPPORTING STRUCTURE Garland Keith, Kingsport, Tenn, assignor to Pid Corporation, Beverly Hills, llalifl, a corporation of California Filed Dec. 29, 1961, Ser. No. 163,316 2 Claims. (til. 118261i) This invention relates to coating apparatus and more particularly to a doctor blade and supporting structure for distributing a uniform layer of coating material on the surface of a coating roll or other surface.

The use of a doctor blade to provide a uniform distribution of material on the surface of a roll or on a flat surface has been relatively common, but the majority of such doctor blade structures have involved the use of a rigid blade which is adjusted in spaced relation to the surface to which the material is to be applied, the distance between the surface and the edge of the blade constituting th thickness of the layer of material applied thereto.

In the instant case it is desired to apply a coating of material to the surface of a roll having ribs extending in a generally longitudinal direction to provide grooves or recesses therebetween to receive the material and in which the outer surface of the deposited material is at or only slightly above the crests of the ribs and consequently the use of rigid blade to distribute the material on such a roll would require extreme accuracy, both in the mounting and concentricity of the roll, as well as in the mounting and adjustment of the doctor blade if contact between the edge of the blade and the crests of the ribs was to be avoided. Obviously, any such contact between the blade and the ribs would result in damage to the roll which would destroy the utility thereof. As a consequence, it has been found that the conventional type of doctor blade structure is not satisfactory for the present use and as a result, the instant novel doctor blade and supporting structure has been developed for the purpose of solving this problem.

It is accordingly an object of the invention to provide a doctor blade and supporting structure which will operate to uniformly distribute a material on a roll or other surface without danger of damage to the roll or to the doctor blade structure.

A further object of the invention is the provision of a doctor blade and supporting structure incorporating means for adjusting the angul-arity of the blade with respect to the surface to which a material is to be applied and also for adjusting the relative spacing between the doctor blade supporting structure and such surface.

A still further object of the invention is the provision of a doctor blade and supporting structure for uniformly distributing a material on the surface of a roll or other surface and in which the portion of the blade in contact with the material comprises one or more flexible elements which may be adjusted to provide a uniform thickness of the material but which will in no way damage the surface as a result of contact between the blade and such surface.

Another object of the invention is the provision of a doctor blade and supporting structure for uniformly distributing a material between longitudinally disposed ribs on the surface of a roll and in which the portion of the blade in contact with the material comprises one or more flexible members which may contact the crests of the ribs without damage thereto.

A further object of the invention is the provision of a doctor blade and supporting structure for uniformly distributing material on the surface of a roll or other surface and in which heating means is provided on the doctor blade structure for heating the same in order to prevent undue cooling or setting of the material in contact with the blade.

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A still further object of the invention is the provision of a doctor blade and supporting structure for uniformly distributing material on a roll or other surface and in which the portion of the blade in contact with the material may be conveniently removed for replacement or repair.

Further objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a front elevational view with parts in section and broken away for greater clarity and showing a doctor blade and supporting structure constructed in accordance with this invention, together with a portion of a roll to which material is uniformly applied by the doctor blade;

FIG. 2 is a top plan view of the structure shown in FIG. 1;

FIG. 3 is a side elevational view with parts broken away for greater clarity and showing the relationship between the doctor blade of this invention and the roll surface on which material is uniformly distributed by such doctor blade;

FIG. 4 is a sectional view taken substantially on the line 4-4 of FIG. 1 and showing certain of the details of the doctor blade supporting structure;

FIG. 5 is a sectional view taken substantially on the line 55 of FIG. 2 and showing further details of the doctor blade, as well as the supporting structure;

FIG. 6 is a top plan view of the doctor blade supporting bar with the heating element applied thereto;

FIG. 7 is a side elevati-onal view of the doctor blade supporting bar and heating element, as well as the doctor blade and showing the manner in which the doctor blade is removably secured thereto;

FIG. 8 is an exploded elevational view showing the doctor blade supporting bar and heating element, as well as the doctor blade; and

FIG. 9 a fragmentary front elevational view with parts broken away and in section for greater clarity and showing one end of the doctor blade supporting bar as well as the portion of the doctor blade secured in place thereon.

With continued reference to the drawings and particularly FIG. 5, there is shown a doctor blade and sup porting structure which may well comprise a pair of spaced opposed supporting members 10 and ill and the supporting member it) may well consist of a body 12 having a slideway 13 therein and a trunnion 14 may be provided with a reduced portion 15 received in an aperture in in the body 12 and secured therein by a set screw 17 or other suitable securing means. The trunnion 14 may be pivotally mounted in an aperture 18 in a side frame member 11% of the apparatus to which the doctor blade of this invention is to be applied and the trunnion l4 may be pivotally secured in the aperture 13 by means of a screw threaded member 2% extending through a washer 21 and threadedly received in an aperture 22 in the trunnion 14. Rotation of the washer 21 with respect to the screw threaded member upon rotation of the trunnion 14 may be prevented by a pin 23 extending through the washer 21 and into the trunnion 14. As best shown in FIG. 3, the body 12 of the supporting member ill is provided with cars 2 and 25 projecting from the body 12 on opposite sides of the axis of the trunnion 14 and the ear 24 is provided with a downwardly projecting adjusting screw 26 provided with a lock nut 27 thereon for engaging the ear 24 to lock the screw 25 in adjusted position and in a similar manner, the car 25 is provided with a downwardly projecting adjusting screw 28 having a lock nut 29 thereon for engaging the ear 25 to lock the screw 28 in adjusted position. A bracket 30 is secured to the upper end of the body 12 by screw threaded fastening means or the like 31 and the bracket 39 projects inwardly of the body 12 away from the trunnion 14 and in its inner end is provided with an aperture 32 in which is rotatably mounted an elevating screw 33 which projects downwardly parallel to the slideway 13 in the body 12 and an operating crank 34 having a hand engaging portion 35 is fixed to the upper end of the elevating screw 33.

In a similar manner, supporting member 11 may well consist of a body 36 having a slideway 37 therein and the body 36 is pivotally mounted on a side frame member 38 having an aperture 39 therein for receiving a trunnion 40 provided with a reduced portion 41 which is received in an aperture 42 in the body 36 and secured in place by a set screw 43 or other suitable securing means. The trunnion 40 is rotatably or pivotally secured in the aperture 39 in the side frame member 38 by means of screw threaded fastening means 44 extending through a washer 45 and threadedly received in a recess 4-6 in the trunnion 40. Rotation of the washer 45 with respect to the screw threaded fastening means 44 is prevented by means of a pin 47 extending through the washer 45 and into the trunnion 40.

The body 36 of the supporting member 11 may be provided with ears 48 and 49 projecting from the body 36 on opposite sides of the axis of trunnion 40 and ear 43 may be provided with a vertically projecting adjusting screw 50 having a lock nut 51 thereon for engaging the car 48 to lock the screw 50 in adjusted position and in a similar manner, the ear 49 may be provided with an adjusting screw 52 which is vertically disposed and provided with a lock nut 53 for engaging the ear 49 to lock the screw 52 in adjusted position.

A bracket 54 is secured to the upper end of the body 36 of the supporting member 11 by screw threaded fastening means or the like 55 and in the inner end of the bracket 54 away from the trunnion 40 there is provided an aperture 56 for rotata'bly receiving an elevating screw 57 to the upper end of which is fixed an operating crank 58 provided with a hand engaging portion 59. It is to be noted that the elevating screw 57 projects downwardly in parallel relationship to the slideway 37 in the body 36 of the supporting member 11.

The opposite ends of a doctor blade supporting bar 69 are slidably received in the slideway 13 and 37 of the supporting members it) and 11 and the supporting bar 69 is provided with threaded apertures 61 and 62 threadedly receiving the elevating screws 33 and 57 respectively.

As best shown in FIG. 7, the doctor blade supporting bar 69 is provided with a downwardly projecting nose portion 63 which projects downwardly from the lower edge of the supporting bar and extends substantially between the apertures 61 and 62. Spaced from the nose portion 63 and also extending downwardly from the lower edge of the supporting bar 66 is an elongated rib 64 which serves to provide a downwardly opening groove 65 between the rib 64 and the nose portion 63. Removably received in the groove 65 is a downwardly projecting doctor blade 66 which is removably secured in the groove 65 by clamping screws 67 threadedly received in the nose portion 63 and projecting therethrough into engagement with the doctor blade 66 to clamp the same against the inner surface of the rib 54. As will be seen from an inspection of FIG. 7, the doctor blade 66 comprises two super-imposed flexible metallic plates 68 and 69, but if desired, such (plates may be made of other than metallic material and it will be noted that the trailing plate 69 terminates above the lower edge of the leading plate 68. The face 70 of the nose portion 63 adjacent the trailing plate 69 is curved downwardly and away from the trailing plate 69 and terminates in an arcuate lower edge 71 on the nose portion 63. The purpose and operation of the particular structure of the doctor blade 66, as well as the particular formation of the nose portion 63 will be presently described.

Since the doctor blade of this invention is commonly utilized in connection with a melted plastic in order to prevent undue cooling of the plastic and setting of the same prior to proper distribution thereof on the surface of a roll or other surface to which the same is to be applied there has been provided a heating element 72 which is elongated and is applied to the surface of the doctor blade supporting bar 60 and the heating element 72 may be conveniently supplied with electrical energy through suitable conductors 73. It will be seen that heat supplied by the heating element 72 will be transferred by conduction through the doctor blade sup porting bar 60 and through the doctor blade 66 to the melted plastic or other material engaged thereby.

A roller 74 is rotatably mounted in the machine to which the doctor blade of this invention is to be applied and as best shown in FIGS. 2 and 3, the adjusting screws 26 and 23 on the supporting member 10, as well as the adjusting screws 59 and 52 on the supporting member 11 engage the side frame members 19 and 38 respectively in order to adjust the angularity of the supporting members 10 and 11, as well as the doctor blade supporting bar 60 and doctor blades 66 with respect to the surface of the roll 74 to which melted plastic or other material is to be applied in a uniform layer by the doctor blade 66. The height of the doctor blade supporting bar 60 and the doctor blade 66 is adjusted in such a manner by operation of the elevating screws 33 and 57 as to bring the lower edge of the doctor blade 66 into contact with the surface of the roll 74 in a manner to deflect or bend the doctor blade 66 into the position shown in FIG. 3 with the trailing plate 69 of the doctor blade 66 engaging the face 70 of the nose portion 63 on the doctor blade supporting bar 60. The roll 74 rotates in the direction of the arrow as shown in FIG. 3, and material applied to the surface of the roll 74 is engaged by the leading plate 68 of the doctor blade 66 in order to distribute such material unformly over the surface of the roll 74 and since the doctor blade of this invention is primarily intended to distribute material over the surface of a roll provided with longitudinally extending spaced ribs, it will be seen that the doctor blade 66 will engage and ride over the crests of such ribs without in any way causing damage to the same, but which, at the same time, will result in providing a uniform layer of material between the ribs on the roll 74 or if desired, extending slightly above the crests of such ribs. The heater 72 will operate to maintain the doctor blade 66 in a heated condition to prevent cooling and setting of the plastic or other material in contact therewith and extremely accurate adjustment of the doctor blade 66 is possible through the medium of the adjusting screws for changing the angularity thereof with respect to the roll 74 and also through the medium of the elevating screws to adjust the spacing between the doctor blade supporting bar 60 and the surface of the roll '74 which will result in adjusting the pressure with which the doctor blade 66 engages the surface of the roll 74. It will also be seen that in the event of damage or wear to the doctor blade 66, the same may be conveniently removed by operation of the clamping screws 67 and replaced by a new or repaired doctor blade merely by inserting the same in the groove 65 and tightening the clamping screws 67. While the doctor blade and supporting structure of this invention has been particularly described with reference to distribution of a material upon a roll, nevertheless, it will be obvious that such doctor blade and supporting structure may be utilized in connection with the distribution of material on a fiat surface, such as a traveling conveyor or any other operation to which a doctor blade of this character will be applicable.

It will be obvious to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is:

1. A doctor blade and supporting structure comprising in combination a pair of spaced opposed supporting members, each member comprising a body having a slideway therein, a trunnion on said body for pivotally mounting the same, projecting ears on said body on opposite sides of the axis of said trunnion, adjusting screws threadedly received in said ears for adjusting the angular position of said body about the axis of said trunnion, a bracket on the upper end of said body, an elevating screw rotatably mounted in said bracket and projecting downwardly parallel to said slide-way, an operating crank fixed to the upper end of said elevating screw, a doctor blade supporting ba-r having the opposite ends thereof slidably received in said slideway, said bar having threaded apertures threadedly receiving said elevating screws, a downwardly projecting nose portion on the lower edge of said bar between said apertures, a rib or the lower edge of said bar between said apertures and spaced from said nose portion to provide a downwardly opening doctor blade receiving groove, a doctor blade removably received in said groove and projecting below said nose portion, and engaging said blade to clamp the same in said groove, said blade comprising two super-imposed flexible metallic plates, the trailing plate terminating above the lower edge of the leading plate, the face of said nose portion adjacent the trailing plate being curved downwardly and away from the trailing plate and terminating in an armate lower edge on said nose portion, whereby upon engagement of the lower edge of said leading plate with a rotating cylinder said blade will bend away from the direction of rotation of the cylinder with the trailing plate engaging the curved base and a portion of the lower edge of said nose portion and a heating element secured to said bar to heat said bar and said blade.

2. A doctor blade and supporting structure comprising in combination a pair of spaced opposed supporting members, each member comprising a body having a slideway therein, a trunnion on said body for pivotally mounting the same, a side frame member disposed adjacent each body and having an aperture for receiving said trunnion for rotation therein, adjusting screws threadedly received in said body for adjusting the angular position of said body about the axis of said trunnion, said adjusting screws engaging said side frame member on opposite sides of said aperture to adjust said body to a desired angular position, a bracket on the upper end of said body, an elevating screw rotatably mounted in said bracket and projecting downwardly parallel to said slideway, a doctor blade supporting bar having opposite ends thereof slidably received in said slideways, said bar having threaded apertures threadedly receiving said elevating screws, a downwardly projecting nose portion on the lower edge of said bar between said apertures, a doctor blade secured to the lower edge of said bar and projecting below said nose portion, said blade comprising a flexible plate, the face of said nose portion adjacent said plate being curved downwardly and away from said plate and terminating in an arcuate lower edge on said nose portion, whereby upon engagement of the lower edge of said plate with a rotating cylinder said plate will bend away from the direction of rotation of the cylinder with said plate engaging the curved face and a portion of the lower edge of said nose portion.

References Cited by the Examiner UNITED STATES PATENTS 1,415,859 5/1922 Bates 15256.51 2,098,750 11/1937 Krahmer 101-169 2,249,089 7/1941 Murray et al 118-401 X 2,361,950 11/1944 Leech.

2,404,689 7/ 1946 Carlsen et al 101-169 2,445,140 7/1948 Hanington 118261 X 2,637,270 5/1953 Bamford 101-157 2,655,102 10/1953 Ross 101-157 2,688,919 9/1954 Kaiser 101-157 2,854,923 10/1958 Huck 118--261 X 2,947,248 8/1960 Fuchs 101-157 3,006,275 10/ 1961 Allen.

3,081,191 3/1963 Smith et a1. 101169 X FOREIGN PATENTS 560,388 4/1957 Italy.

CHARLES A. WILLMUTH, Primary Examiner.

RICHARD D. NEVIUS, Examiner. 

1. A DOCTOR BLADE AND SUPPORTING STRUCTURE COMPRISING IN COMBINATION A PAIR OF SPACED OPPOSED SUPPORTING MEMBERS, EACH MEMBER COMPRISING A BODY HAVING A SLIDEWAY THEREIN, A TRUNNION ON SAID BODY FOR PIVOTALLY MOUNTING THE SAME, PROJECTING EARS ON SAID BODY ON OPPOSITE SIDES OF THE AXIS OF SAID TRUNNION, ADJUSTING SCREWS THREADEDLY RECEIVED IN SAID EARS FOR ADJUSTING THE ANGULAR POSITION OF SAID BODY ABOUT THE AXIS OF SAID TRUNNION, A BRACKET ON THE UPPER END OF SAID BODY, AN ELEVATING SCREW ROTATABLY MOUNTED IN SAID BRACKET AND PROJECTING DOWNWARDLY PARALLEL TO SAID SLIDE-WAY, AN OPERATING CRANK FIXED TO THE UPPER END OF SAID ELEVATING SCREW, A DOCTOR BLADE SUPPORTING BAR HAVING THE OPPOSITE ENDS THEREOF SLIDABLY RECEIVED IN SAID SLIDEWAY, SAID BAR HAVING THREADED APERTURES THREADEDLY RECEIVING SAID ELEVATING SCREWS, A DOWNWARDLY PROJECTING NOSE PORTION ON THE LOWER EDGE OF SAID BAR BETWEEN SAID APERTURES, A RIB OR THE LOWER EDGE OF SAID BAR BETWEEN SAID APERTURES AND SPACED FROM SAID NOSE PORTION TO PROVIDE A DOWNWARDLY OPENING DOCTOR BLADE RECEIVING GROOVE, A DOCTOR BLADE REMOVABLY RECEIVED IN SAID GROOVE AND PROJECTING BELOW SAID NOSE PORTION, AND ENGAGING SAID BLADE TO CLAMP THE SAME IN SAID GROOVE, SAID BLADE COMPRISING TWO SUPER-IMPOSED FLEXIBLE METALLIC PLATES, THE TRAILING PLATE TERMINATING ABOVE THE LOWER EDGE OF THE LEADING PLATE, THE FACE OF SAID NOSE PORTION ADJACENT THE TRAILING PLATE BEING CURVED DOWNWARDLY AND AWAY FROM THE TRAILING PLATE AND TERMINATING IN AN ARCUATE LOWER EDGE ON SAID NOSE PORTION, WHEREBY UPON ENGAGEMENT OF THE LOWER EDGE OF SAID LEADING PLATE WITH A ROTATING CYLINDER SAID BLADE WILL BEND AWAY FROM THE DIRECTION OF ROTATION OF THE CYLINDER WITH THE TRAILING PLATE ENGAGING THE CURVED BASE AND A PORTION OF THE LOWER EDGE OF SAID NOSE PORTION AND A HEATING ELEMENT SECURED TO SAID BAR TO HEAT SAID BAR AND SAID BLADE. 